Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030, USA.
J Clin Invest. 2011 Apr;121(4):1524-34. doi: 10.1172/JCI44327. Epub 2011 Mar 7.
The in vivo therapeutic efficacy of DC-based cancer vaccines is limited by suboptimal DC maturation protocols. Although delivery of TLR adjuvants systemically boosts DC-based cancer vaccine efficacy, it could also increase toxicity. Here, we have engineered a drug-inducible, composite activation receptor for DCs (referred to herein as DC-CAR) comprising the TLR adaptor MyD88, the CD40 cytoplasmic region, and 2 ligand-binding FKBP12 domains. Administration of a lipid-permeant dimerizing ligand (AP1903) induced oligomerization and activation of this fusion protein, which we termed iMyD88/CD40. AP1903 administration to vaccinated mice enabled prolonged and targeted activation of iMyD88/CD40-modified DCs. Compared with conventionally matured DCs, AP1903-activated iMyD88/CD40-DCs had increased activation of proinflammatory MAPKs. AP1903-activated iMyD88/CD40-transduced human or mouse DCs also produced higher levels of Th1 cytokines, showed improved migration in vivo, and enhanced both antigen-specific CD8+ T cell responses and innate NK cell responses. Furthermore, treatment with AP1903 in vaccinated mice led to robust antitumor immunity against preestablished E.G7-OVA lymphomas and aggressive B16.F10 tumors. Thus, the iMyD88/CD40 unified "switch" effectively and safely replaced exogenous adjuvant cocktails, allowing remote and sustained DC activation in vivo. DC "licensing" through iMyD88/CD40 may represent a mechanism by which to exploit the natural synergy between the TLR and CD40 signaling pathways in DCs using a single small molecule drug and could augment the efficacy of antitumor DC-based vaccines.
基于树突状细胞（DC）的癌症疫苗的体内治疗效果受到不成熟 DC 成熟方案的限制。虽然全身性给予 TLR 佐剂可增强基于 DC 的癌症疫苗的疗效，但也可能增加毒性。在这里，我们构建了一种可诱导的、用于 DC 的复合激活受体（称为 DC-CAR），其包含 TLR 衔接子 MyD88、CD40 细胞质区域和 2 个配体结合的 FKBP12 结构域。施用可渗透脂质的二聚化配体（AP1903）诱导该融合蛋白的寡聚化和激活，我们将其命名为 iMyD88/CD40。AP1903 给药可使疫苗接种小鼠中的 iMyD88/CD40 修饰的 DC 持续且靶向激活。与常规成熟的 DC 相比，AP1903 激活的 iMyD88/CD40-DC 中促炎 MAPK 的激活增加。AP1903 激活的 iMyD88/CD40 转导的人或鼠 DC 还产生更高水平的 Th1 细胞因子，显示体内迁移改善，并增强抗原特异性 CD8+T 细胞反应和固有 NK 细胞反应。此外，在疫苗接种小鼠中用 AP1903 治疗可导致针对预先建立的 E.G7-OVA 淋巴瘤和侵袭性 B16.F10 肿瘤的强大抗肿瘤免疫。因此，iMyD88/CD40 统一“开关”有效地且安全地替代了外源佐剂鸡尾酒，允许体内远程和持续的 DC 激活。通过 iMyD88/CD40 对 DC 进行“许可”可能代表一种机制，可利用 TLR 和 CD40 信号通路在 DC 中的天然协同作用，使用单一小分子药物，并可增强基于抗肿瘤 DC 的疫苗的疗效。
